JPH01150211A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To prevent deformation of an insulating layer and to improve the yield of production by executing the curing heat treatment of a heat-resistant polyimide resin which constitutes the insulating layer while impressing a magnetic field thereto in the track width direction of magnetic poles, thereby lowering the heat treatment temp. after the production process to <=350 deg.C. CONSTITUTION:A lower magnetic layer 2 on a nonmagnetic substrate 1 is formed of an amorphous CoTaZr film and the thermally stable heat-resistant polyimide resin PIQ is used for the insulating layer 5. The curing heat treatment of the insulating layer 5 is executed at 350 deg.C while the magnetic field of DC or AC is impressed thereto in the track width direction of the magnetic poles. As a result, the heat treatment temp. after the production process is lowered to <=350 deg.C from >=380 deg.C of the conventional method. The deformation of the insulating layer 5 is, therefore, prevented and the yield of the production of the thin-film magnetic head is increased to >=90%.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thin film magnetic head suitable for high-density magnetic recording, and in particular, a thin film magnetic head that uses an amorphous magnetic film and a heat-resistant polyimide resin for the insulating layer. It relates to a thin film magnetic head.

[Conventional technology]

There has been remarkable progress in increasing the density and performance of magnetic recording. In the field of magnetic disk drives for large computers, significant improvements in recording density have made it possible to increase capacity. In magnetic disk drives, it is essential to use thin-film heads that have lower inductance and higher high-frequency magnetic permeability than conventional ferrite bulk heads, and can be processed into narrow track widths.

In thin-film heads, it is necessary to make the magnetic pole thinner in order to improve resolution as recording density increases, and magnetic saturation easily occurs at the thin magnetic pole tip. A thin film head is now required.

Conventionally, Ni-Fe alloy films (permalloy films) have been mainly used as magnetic films for thin film heads.
The Fe-based alloy film has excellent corrosion resistance, but the saturation magnetic flux density is 1. Ni-Fe, which is OT, is no longer able to cope with future increases in saturation magnetic flux density.

In recent years, amorphous sputtered films have been developed as high-performance magnetic films with high saturation magnetic flux density. Among these, Zr-based alloys have particularly excellent heat resistance and excellent characteristics as magnetic films for magnetic heads, compared to amorphous alloys whose vitrification elements are metalloid elements such as B, Si, and P. Specifically, the amorphous alloy is represented by the composition formula M a T b Z r. Here, M is Go, Fe, N, which has a magnetic moment.
i, and T is a transition metal other than M and Zr. Such vitrification elements are mainly Zr.
Regarding the amorphous alloy consisting of
Among these Zr-based amorphous alloys described in 9 and JP-A-56-84439, M is Go.
The o-Zr amorphous material has a high saturation magnetic flux density and is an excellent magnetic material. However, the magnetostriction constant of this amorphous alloy is 2
Since V and Nb exhibit relatively large values of ~4X10-6, they make a negative contribution to the magnetostriction constant of the amorphous alloy as additive elements T.

By using elements such as Ta, Mo, and W, an amorphous alloy with a magnetostriction constant of approximately O can be obtained.

In Japanese Patent Application Laid-Open No. 62-107415, a thin film magnetic head is manufactured using these amorphous magnetic films.

[Problem that the invention seeks to solve]

The above conventional technology uses heat-resistant polyimide resin PIQ (manufactured by Hitachi Chemical Co., Ltd. vA) for the thin film magnetic head insulating layer.

PIQ is a thermosetting resin and requires 350℃ to cure
It needs to be heat treated. Conventionally, this heat treatment is performed without a magnetic field, and at this time, the magnetic permeability of the amorphous film is reduced to 300 or less. Therefore, in the past, heat treatment in a magnetic field was performed after the manufacturing process of the thin film magnetic head was completed to cancel out the influence of the thermal history caused by the heat treatment of PIQ and improve the magnetic permeability of the magnetic film. However, the heat treatment temperature of this heat treatment needs to be higher than the heat treatment temperature caused by the thermal covering history. That is, the heat treatment temperature in a magnetic field is at least 380°C.
I needed to do more than that.

However, when heat treatment in a magnetic field at 380° C. or higher is applied after the thin film head manufacturing process, the insulating layer formed by PIQ is deformed, resulting in a problem in that the production yield of the thin film head becomes 30% or less.

The object of the present invention is to use an amorphous material for the magnetic pole and a PIQ for the insulating layer.
An object of the present invention is to provide a head using a thin film head in which the heat treatment temperature after the thin film head process is 350° C. or lower, and the insulating layer is not deformed. [Means for solving the problem] In order to solve the above problem, in the PIQ curing process,
If heat treatment is performed while applying a magnetic field in the track width direction of the thin film head, the temperature of the heat treatment in the magnetic field after forming the thin film head can be reduced by 3.
The temperature can be lowered to 50℃, and the thin film head formation yield can be reduced to 9.
It can be set to 0% or more.

[Effect]

It is thought that performing the PIQ hardening heat treatment while applying a magnetic field makes the anisotropy of the magnetic film more uniform than in conventional methods. The reason for this is thought to be as follows. Since the magnetic film of the thin film head is processed into a magnetic pole shape with a width of 20 μm to 100 μm, a magnetic domain structure as shown in FIG. 2 is realized under the influence of one demagnetizing field. Inside each magnetic domain, magnetization is oriented in the direction indicated by the arrow. in this case.

When heat treatment is performed in a non-magnetic field, each magnetic domain undergoes treatment similar to heat treatment in a magnetic field due to the internal magnetic field of magnetization. Therefore, a state in which the direction and magnitude of anisotropy are distributed is realized inside the magnetic pole.

On the other hand, when a magnetic field sufficient to saturate the pole magnetic film in the direction of the pole track width is applied, the pole becomes a single domain state.

When heat-treated in this state, the anisotropy inside the magnetic pole becomes uniform because the magnetic field is heat-treated in a uniform magnetic field.Considering two heat-covering histories of 6 or more, the latter is better.
It can be seen that this effect can be easily canceled out by heat treatment in a magnetic field after forming the thin film head. Therefore, according to the present invention, the temperature of heat treatment in a magnetic field after forming a thin film head can be lowered;
The formation yield of thin film heads can be improved.

〔Example〕

The present invention will be explained in detail below using examples.

FIG. 3 shows a cross-sectional view (A) and a top view (B) of a thin-film magnetic head using a Co9zTasZra amorphous film as a magnetic pole. This thin pancreatic head is A QxOs-T i C.

A lower magnetic layer 2 is formed on a nonmagnetic substrate 1 such as Zr()z. The lower magnetic layer 2 was formed of a CoezTaaZrs amorphous film. CO9! The TaδZra amorphous film is formed by a bipolar high-frequency sputtering method, and then processed into a magnetic pole shape by an ion milling method. At this time.

Since the amorphous magnetic film has uniaxial anisotropy, the track width direction 8 of the magnetic pole was made to coincide with the easy axis direction of the magnetic film. Furthermore, a gap layer 3 was formed using AQzOa and 5ift.

Next, a conductive coil 4 is formed using AQ and Cu. It is necessary to provide an insulating layer 5 to maintain insulation between the conductive coil 4 and the upper magnetic layer 6. here.

Heat-resistant polyimide resin PIQ, which can flatten the unevenness created by the conductive coil 4 and is thermally stable, was used. P
Since IQ is fluid, it is necessary to perform heat treatment to harden it. Typically, after applying PIQ using a spinner, heat treatment is performed at 200°C, and then further heat treatment is performed at 350°C.

At this time, no magnetic field was applied.

Furthermore, an upper magnetic layer 6 is provided thereon. As the upper magnetic layer 6, similarly to the lower part, a CoezTasZ ra amorphous film was formed by the bipolar high frequency sputtering method, and then processed into a magnetic pole shape by the ion milling method.

In addition, like the lower magnetic pole, the track width direction 8 of the magnetic pole
is made to coincide with the easy axis direction of the magnetic film.

Thereafter, after forming the protective film 8 of AfizOa, heat treatment was performed in a magnetic field in order to improve the soft magnetic properties of the magnetic film. Heat treatment in a magnetic field was performed by applying a magnetic field in the track width direction 8 of the thin film head at 11°C (heat treatment 1), and then applying a magnetic field in a direction perpendicular to the track width direction 8 and heat treatment at 12°C (heat treatment 2). Time passed. The magnetic field is a 5 kOe DC magnetic field. Furthermore, chip processing and polishing are performed to form a thin film head.

FIG. 4 shows the relationship between the heat treatment temperature in a magnetic field and the reproduction output of the thin film head. Evaluation of reproduction output is coercive force 4000
It was carried out with a coating medium of Sea Fezes of E. The playback output is expressed as a relative output with the maximum output being 1.

When the heat treatment temperature T1 of heat treatment 1 is 350°C or less, T2
No matter how many times you try to increase the output, you will only be able to obtain less than half of the maximum output that can be obtained with this thin-film head. However, Tz=3
At 80℃, T! The maximum output was achieved when the temperature was 340°C. In other words, in the thin film head shown in Fig. 3 that uses PIQ for the insulating layer, if the PIQ hardening heat treatment is performed in the absence of a magnetic field, the temperature of the subsequent heat treatment for improving the magnetic film properties should be 350'C or higher. It turns out that without it, sufficient playback output cannot be obtained.

Figure 5 shows the relationship between the magnetic field heat treatment temperature T1 and the defective rate of the thin film head due to deformation of the insulating layer (defective rate = 100 - yield). When aTx is 350°C or higher, the defective rate increases rapidly. At Tz=380°C, the defective rate is 70% or more. Therefore, with conventional thin-film heads, the yield of heads capable of providing sufficient reproduction output was 30% or less.

Next, a thin film head having the same structure as that shown in FIG. 3 was fabricated, in which heat treatment was performed by applying a DC magnetic field of 5 kOe in the track width direction of the magnetic pole during hardening heat treatment of the insulating layer PIQ. Heat treatment to improve the properties of the magnetic film is performed on the protective film 8 of AQzOs.
This was done after forming the . At this time, a DC magnetic field of 5 k Oe was applied in a direction perpendicular to the track width direction of the magnetic pole.

FIG. 1 shows the relationship between the magnetic field heat treatment temperature T for improving the characteristics of the magnetic film and the reproduction output of the head.

The reproduction output was evaluated using a Sea Fezes coating medium having a coercive force of 4000e as in FIG. 4. The playback output is the third
It is shown as a relative output with the maximum output in the figure as 1, and
The heat treatment in the magnetic field was performed for 1 hour.

The reproduction output reached its maximum value at the processing temperature of 350° C., and this value was equivalent to the maximum reproduction output shown in FIG. 4. That is, it has been found that according to the present invention, the temperature of the magnetic film in the magnetic field can be lowered to 350° C. or lower. Therefore, according to the present invention, the yield of heads that can obtain sufficient reproduction output is 90.
% or more.

In addition, in order to saturate the magnetic pole of the thin film head, 5 koa is required.
It was necessary to apply a magnetic field larger than that.

Figure 6 shows the change in playback output over time when the same playback output was selected from those that were heat-treated in a magnetic field during the hardening heat treatment of PIQ and those that were not. compared. It was revealed that PIQ that was heat-treated in a magnetic field during the hardening heat treatment showed smaller changes over time than those that were not heat-treated.

Other amorphous films, such as CoNbZr.

The same was true for thin film heads using CoWZr as magnetic poles.6 Therefore, it is thought that the above phenomenon is generally applicable to thin film heads using amorphous films.

〔Effect of the invention〕

According to the present invention, in a thin film head using a heat-resistant polyimide resin such as PIQ for the insulating layer and an amorphous magnetic film for the magnetic pole, the heat treatment temperature of the amorphous magnetic film in a magnetic field is 35°C.
Since the temperature can be kept at a low temperature of 0° C. or lower, deformation of the insulating layer can be prevented and the yield of thin film head formation can be improved. Furthermore, the thin film head of the present invention has less deterioration over time than the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the magnetic field heat treatment temperature T of a magnetic film according to an embodiment of the present invention and the reproduction output of the head, FIG. 2 is a schematic diagram of the magnetic domain structure formed on the magnetic pole, and FIG. A sectional view and a top view of a thin film magnetic head according to an embodiment of the present invention, FIG. 4 is a characteristic diagram showing the relationship between the heat treatment temperature in a magnetic field and the reproduction output of the thin film magnetic head, and FIG. 5 shows the relationship between the heat treatment temperature in a magnetic field and the reproduction output. Figure 6 shows the relationship between the failure rate of thin-film heads due to deformation of the insulating layer, and the characteristic rate of change over time in the reproduction output of heads that were heat-treated in a magnetic field during the PIQ hardening process and those that were not.
Unexpected treatment temperature 7 ('C second 312th) (b) Fourth heat treatment temperature T7

Claims (1)

[Claims] 1. A thin film magnetic head having a magnetic pole made of an amorphous magnetic film, a gap layer, a conductive coil, and an insulating layer made of a heat-resistant polyimide resin to maintain electrical insulation between the magnetic pole and the conductive coil. A thin film magnetic head characterized in that the heat-curing treatment of the heat-resistant polyimide resin is performed while applying a direct current or alternating current magnetic field in the track width direction of the magnetic pole. 2. After the heat treatment for curing the heat-resistant polyimide resin, heat treatment is performed in a magnetic field while applying a direct current or alternating current magnetic field in a direction perpendicular to the track width direction of the magnetic pole. The thin film magnetic head described. 3. The thin film magnetic head according to claims 1 or 2, wherein the magnetic field has a magnitude of 95 kOe or more. 4. The scope of claims characterized in that the amorphous magnetic film is a CoTaZr-based amorphous film, and the temperature of the heat treatment in the magnetic field after the curing treatment of the heat-resistant polyimide resin is 330°C or more and 350°C or less The thin film magnetic head according to items 2 and 3.